Encoders

Encoders are devices that convert movement or position into an electronically encoded pattern that can be read by a circuit or processing system. They are a type of sensor, and can form part of an electro-mechanical control system as they provide a mechanism to obtain feedback. An example of this is a Servo. A Servo is a motor that has an encoder attached to its shaft that provides positional feedback. The positional feedback is compared to the setting required, and an error signal is generated. The Motor speed is changed to respond so as to minimize this error. Encoders are available in several different forms. This includes Magnetic, Optic, and Mechanical Encoders.

A Magnetic Encoder is an electromagnetic mechanical device that detects the distance between two or more magnetic poles to detect the position of a rotating shaft. They are also available as Magnetic Linear Encoders for precision position feedback in applications such as woodworking, stone cutting, sawing, packaging and automation and assembly systems. Magnetic Encoders are usually intended to operate in harsh environments while providing precise measurements. They tend to run on the Hall Effect or the Magnetoresistive Effect. The Hall Effect is a physical phenomenon where a voltage (called the Hall Voltage) can be produced in electrical conductors and semiconductors because of charge carriers being forced in a direction perpendicular to a magnetic field.

A Mechanical Encoder is an electromechanical device that converts position or movement into a signal or signals that can be read by an electronic circuit or processor system. There are two main types of mechanical encoders. Rotary Encoders detect position or movement by converting the angular position of a shaft. Linear Encoders are read-heads that encode position associated with a scale – and are uncommon as other technologies like optical and magnetic encoders are better suited for applications where linear encoders would be used (for example CNC Mills and Gantry Tables).

An Optical Encoder is a device that consists of an LED light source, and a photodiode detector enclosed in a light sealed package. They tend to be rotary encoders – a central shaft spinning a disk with a periodically spaced window pattern, but they can also be linear encoders for reading things like code strips. They can be panel mounted, designed to fit mechanically on a shaft or knob or part of some mechanical arrangement to detect motion.